I have an area of lawn about 60x40 that has had a consistent dead patch in one area since we moved in 1 year ago, and now additional dry/dead spots have appeared. The soil is mostly clay. I aerated 11 months ago and again two weeks ago. I fertilized last fall, this spring, and again after I aerated two weeks ago. I am planning to reseed, but want to fix the problem first.
1) I think the zone may have too many heads. While other lawn zones have 6-7, this one has 10. The heads are Rainbirds (T-Bird T-40 Part Circle). I've checked and adjusted the spray pattern of the heads earlier today. Most of the dry areas appear to have been received less than optimal coverage.
2) I am on a well. Before the sprinklers kick in, the 88 gal tank is at 62 PSI, and the sprinklers are covering the area just fine. After the sprinklers are on for a couple of minutes, the pressure drops to 20 PSI, and the sprinklers cover about 1/2 the arc they were covering at first. The well pump is 15 years old, and I wonder if it might be at fault. (The well and pump tested OK 1 year ago when I bought the place.)
3) With no other water on, the hose will fill a 1 gal bucket in 5 seconds; with the sprinklers on, 12 seconds. The sprinklers put out about 1/2 inch of water per hour. I was running this zone at 25 minutes 3x/week, so the lawn might not have been getting enough water. (We live in the Central Valley, outside Stockton, CA, and the avg temp this time of year is about 95 every day. [8D])
Here are pictures of two areas of the lawn from last July, each accompanied by a picture from today. You can see the lawn has many more brown spots.
The first is looking south-southeast. Note the much bigger brown spot under the tree in the center from last year to today:
Last year:
Today:
The second is looking south-east from the same location. Note that there is a small grove of Sequoia trees in the background of this picture:
Last year:
Today:
Maybe I've identified and fixed the problem by adjusting the sprinkler heads. But maybe there's something else I should look at. Any recommendations/suggestions are sincerely appreciated.
Brian T. Phelps
http://garnica.phelpsinc.com